Wrong Reference, bad Estimation

While coaching one of my teams I concluded we had a problem with becoming more predictable. Sprints goals were not met, and the Velocity changed from Sprint to Sprint. I found out that different Development Team members were using different references while estimating their User Stories. The way of determining their references differs from person to person.

A few examples were the references being based on:

Gut feeling;

The first User Story estimated every session;

Always the same User Story;

The results of the previous Sprint.

To make a long story short, some alignment was missing about a reference for effort estimation.

Following this, I decided to create an exercise to show the team what’s happening every time they estimate their User Stories. The goal of the exercise was to let the Team understand the importance of a single reference, and its use to be able to make better forecasts when doing effort estimation. I’m going to share this exercise with you.

The exercise is quite simple. Split your Team into a least two groups (everybody present during the retro can join this exercise). Within my specific situation, I decided to split the Team into two separate groups. I created two decks of cards for the exercise, which contained the names of different countries. (of course, you can easily extend the number of decks).

The exercise step by step:

Start by handing out the decks together with a deck of Planning Poker cards*.

Ask the group’s first to order the countries relatively, based on the size of their surface. Using the internet to gain information about the given countries is allowed, Wikipedia for example. (You can tell them it’s like Refining the Product Backlog)

Make sure they write down the size of every country.

When they are finished ask the group to give each country a certain amount of weight relative to the others, by using the Planning Poker cards.

When all groups are finished ask them to compare their results with each other and see if they notice some remarkable things within their outcome.

Maybe you did already notice, but you can find Greece in both decks. This is the trick of the exercise. When the groups relative ordered their deck, Greece will have a different weight when comparing both decks. During my session, Greece was estimated as “1” within the Spain deck and estimated “3” within the Croatia deck. Seeing this, the groups came to the conclusion their selves that Greece had a three times higher relative estimated surface when comparing both groups. They also concluded that the effort they were estimation for User Stories was shifted each time they were estimating, and thereby not very accurate.

As a follow up to this meeting, the Team decided to define a Reference Story within the next Refinement Event. I explained to the Team to pick a Story that was easy to finish and is average of size. Even more important, everybody must have a good feeling about the effort it took to finish it.

Conclusion

In my opinion, becoming more predictable starts with alignment between each other. Key of course is to keep communicating, instead of letting a tool become the decisive factor. (individuals and interactions over processes and tools). But, using “the same reference” during relative estimating will definitely help to make better estimations or to speed up conversations easier. Using the same reference also increases the accuracy of estimation and will make estimation easier because you can compare it with earlier obtained Team Velocity.